Researchers have shown that a new treatment for breast cancer using an antibody linked to a cytotoxic drug is as effective as the previous combination, but with less side effects. The study was published in JAMA Oncology.
The development of treatment with antibodies directed towards HER2 positive breast cancer trastuzumab and pertuzumab, has proven the possibility of improved treatment and cure of this cancer type if these antibodies are combined with chemotherapy, often taxaner. Preoperative (neoadjuvant) treatment with this combination confers complete response in a high proportion of cases. Trastuzumab emtansine (T-DM1) consists of trastuzumab (T) and the cytotoxic substance emtansine (DM1) which clinical trials have shown have good efficacy and low toxicity.
The randomised phase II study PREDIX HER2 was conducted at 9 Swedish clinics to investigate the effect (the proportion of complete response after neoadjuvant treatment) of this treatment in relation to frequency and degree of side effects. The standard treatment was a combination of docetaxel, trastuzumab and pertuzumab which was compared with T-DM1 as experimental treatment, and patients received 6 treatments every 3rd week. The treatment effect was monitored with mammography and PET-CT with 18- fluorodeoxyglucose (18F-FDG). Tissue and blood samples were regularly taken from the patients for later analysis.
The study showed that the effect measured as pathologic complete response was similar in both treatment groups. With T-DM1 treatment, the frequency and degree of side effects was significantly lower and quality of life was higher during treatment. After a median follow up time of 40,4 months no difference was observed between the treatment groups.
In conclusion, the study showed that both treatments were equally efficient, but with fewer side effects in patients treated with T-DM1. A phase III study will allow definitive conclusions to be drawn regarding the efficiency. Meanwhile, the collected samples are being analysed to investigate factors which can explain the response in individuals.
Source: Karolinska Institute
